Alternating access in maltose transporter mediated by rigid-body rotations.
Alternating access in maltose transporter mediated by rigid-body rotations.
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DOI：
10.1016/j.molcel.2009.01.035
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发表时间：
2009-02-27
期刊：
影响因子：
16
通讯作者：
Chen, Jue
中科院分区：
文献类型：
--
作者：
Khare, Dheeraj;Oldham, Michael L.;Orelle, Cedric;Davidson, Amy L.;Chen, Jue
ATP结合盒转运蛋白通过交替进入机制将ATP水解与底物转运偶联，但转运循环中构象变化的性质仍然难以捉摸。以前，我们报道了麦芽糖转运蛋白MalFGK 2的结构在一个向外的构象，其中跨膜（TM）螺旋轮廓的底物结合口袋打开朝向周质表面和ATP是准备水解沿着封闭的核苷酸结合二聚体界面。在这里，我们报告的无核苷酸麦芽糖转运蛋白的结构中，底物结合口袋只能从细胞质和核苷酸结合界面是开放的。相同的运输结晶在两种不同的构象的比较表明，交替访问涉及耦合到关闭和开放的核苷酸结合域接口的TM子域的刚体旋转。比较还表明，点突变，使结合蛋白独立的运输线动态界面在TM区域。
ATP-binding cassette transporters couple ATP hydrolysis to substrate translocation through an alternating access mechanism, but the nature of the conformational changes in a transport cycle remains elusive. Previously we reported the structure of the maltose transporter MalFGK2 in an outward-facing conformation where the transmembrane (TM) helices outline a substrate-binding pocket open towards the periplasmic surface and ATP is poised for hydrolysis along the closed nucleotide-binding dimer interface. Here we report the structure of the nucleotide-free maltose transporter in which the substrate binding pocket is only accessible from the cytoplasm and the nucleotide-binding interface is open. Comparison of the same transporter crystallized in two different conformations reveals that alternating access involves rigid-body rotations of the TM subdomains that are coupled to the closure and opening of the nucleotide-binding domain interface. The comparison also reveals that point mutations enabling binding-protein independent transport line dynamic interfaces in the TM region.
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DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
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通讯作者：
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影响因子：
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56.9
作者：
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影响因子：
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作者：
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